Pneumonia

Pneumonia is a serious lung infection. Treatment with antibiotics is usually needed. If you are normally well, it is likely that you will make a full recovery. Some severe cases are life-threatening. When someone is in poor health or very old, pneumonia can make them very ill and the infection is more likely to be life-threatening.

Cross-section diagram showing lungs and airways

Pneumonia is an inflammation of the lung tissue. It is usually due to infection. Pneumonia tends to be more serious than bronchitis. Bronchitis is an inflammation or infection of the large airways - the bronchi (see diagram). Sometimes bronchitis and pneumonia occur together which is called bronchopneumonia.

Pneumonia is commonly caused by an infection with a bacterium or virus. There are 3 or 4 different bacteria that are the most common causes of pneumonia. There is also a well-known group of bacteria that causes pneumonia in about 3 out of 10 cases. They are called atypicals. Other germs such as fungi, yeasts, or protozoa can sometimes also cause pneumonia.

Rarely, non-infective pneumonia is caused by inhaling poisons or chemicals.

You may breathe in some bacteria, viruses, or other germs. If you are normally healthy, a small number of germs usually doesn't matter. They will be trapped in your sputum and killed by your immune system. Sometimes the germs multiply and cause lung infections. This is more likely to happen if you are already in poor health. For example: if you are frail or elderly; if you have a chest disease; if you have a low immunity to infection. Low immunity can be caused by such things as alcohol dependence, AIDS, or another serious illness. However, even healthy people sometimes develop pneumonia.

  • If you were previously well. With treatment, you are likely to make a full recovery. However, some bacteria, viruses, and other germs are more serious than others. Some people become very ill and require hospital admission. Occasionally, some people who were previously well die from pneumonia.
  • If you are already in poor health. You are more likely to become seriously ill with pneumonia. Pneumonia is a common cause of death in people who are already unwell - for example, people in the late or terminal stages of a cancer.

Typical symptoms are cough, fever, sweats, shivers, being off your food and feeling generally unwell. Headaches and aches and pains are common. You usually make more sputum. This may become yellow/green coloured and is sometimes bloodstained.

You may become breathless, breathe fast and develop a tight chest. A sharp pain in the side of the chest may develop if the infection involves the pleura. (This is the membrane between the lung and the chest wall.) A doctor may hear crackles in the chest when listening with a stethoscope.

Treatment at home

Treatment at home may be fine, if you are normally well and the pneumonia is not severe.

An antibiotic such as amoxicillin is prescribed when pneumonia is suspected. Bacterial infection is a common cause and antibiotics kill bacteria. Amoxicillin is usually effective against the most common causes. If it doesn't seem to be effective and your doctor suspects a less common bacterium, they may change it. If you are allergic to penicillin (amoxicillin is a type of penicillin) your doctor will prescribe an alternative that works just as well. Antibiotic treatment is usually effective and you can expect to recover fully. Symptoms should improve after 3 days if the treatment is working. You may feel tired for a while after the infection has cleared. If the symptoms persist longer than 3 weeks, you should ask your doctor to check you again.

Have lots to drink, to avoid becoming dehydrated.

Take regular paracetamol to ease fever and headaches.

Let a doctor know if symptoms do not improve over the following three days.

Hospital treatment

Hospital admission may be advised if you have severe pneumonia, or if symptoms do not quickly improve after you have started antibiotic treatment. Also, you are more likely to be treated in hospital if you are already in poor health, or if an infection with a more serious infecting germ is suspected. For example, if infection with Legionella pneumophila (the bacterium that causes Legionnaires' disease) is suspected.

  • A chest X-ray may be taken to confirm the diagnosis and the extent of the infection.
  • Blood tests and sputum tests may be taken to find which bacterium is causing the pneumonia. This helps to decide which antibiotic is best to use. Sometimes the bacterium that is causing the pneumonia is resistant to the first antibiotic. A switch to another antibiotic is sometimes needed.
  • Sometimes oxygen and other supportive treatments are needed if you have severe pneumonia. Those who become severely unwell may need treatment in an intensive care unit.
  • When you return home, even though the infection is treated, you may feel tired and unwell for some time.

Immunisation against the pneumococcus (the most common cause of bacterial pneumonia) and the annual influenza (flu) virus immunisation are advised if you are at greater risk of developing these infections.

See separate leaflets called 'Pneumococcal Immunisation' and 'Influenza Immunisation' for further details.

Cigarette smoke damages the lining of the airways and makes the lungs more prone to infection. So stopping smoking will lessen your risk of developing lung infections.

If you are well enough to be looked after at home, your outlook is very good. Fewer than 1 person in 100 will die as a result of pneumonia. Those who die tend to be older people, or those who also have other health problems.

If you need to be looked after in hospital, the outlook is not quite as good. 1 person in 10-20 may die because of their pneumonia. Again, these will usually be people who were unwell before they had pneumonia, or the elderly.

If the pneumonia is very severe, or caused by an aggressive type of bacterium (such as legionella) you may need to be moved to an intensive care unit in the hospital. In these cases the outlook is much worse. Unfortunately, as many as half of these people may die.

If you are normally well, but then develop recurrent bouts of pneumonia, it may be the first sign of a problem of your lung or immune system. Some tests of your immune system may be advised if pneumonia recurs for no apparent reason.

Original Author:
Dr Tim Kenny
Current Version:
Peer Reviewer:
Prof Cathy Jackson
Last Checked:
20/04/2012
Document ID:
4491 (v40)
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